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Discussion Starter · #1 ·
I have one complaint with my 2008 LT. When cruising on highways, and climbing hills, the transmission seems to "hunt" for the right gear. I don't mind a downshift when needed, but it seems to want to drop from 4th to 3rd, but it takes forever, while the engine revs and doesn't seem to get into gear.

I have a pcm tune with "2" shift firmness, and have no problem with other shifts.

I have read much about transmission mods, but I need some advice to help with this issue. Thanks.
 

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Basic Vendor- Skid Plates
2007 chevy trailblazer_ls
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Try a non-tuned PCM... If it still has the issue, get the PCM un-tuned and take it to the dealership for warranty ('08, you're still under 100k, right?)...

This is the reason I'm not getting a tune until my 5-years or 100k are up... the GM tech can now see the "tune", and they can void your warranty for it, if the tune is related to something that goes wrong...

Mike
 

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Discussion Starter · #3 ·
Thanks, but I am confident it has nothing to do with the pcm tune. I was having the same problem before the tune, and that is one of the reasons I got the tune. It made the upshifts firmer, but has no effect on this issue.

There must be some way to address this issue.
 

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2007 chevy trailblazer_ls
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What you might be experceing is a torque converter lock up issue and not a gear hunt problem The TC ia "pulse with modulated" in 4th gear and never locks up more than 95% You may be seeing the rpms jump up when the tc unlocks going up a hill and takes its sweet time locking back up again. Try putting it in third and see if the problem goes away. In third gear the tc can lock up 100% Another thing to try is just touch the brake pedal while driving in 4th at 65 mph this will unlock the tc. see if the rpms go up the same as when you think that it has downshifted to 3rd. Jay
 

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Discussion Starter · #5 ·
I definitely think this is a TC lockup issue. I can manually shift to 3 and it stops. My question is: What, if anything, can be done about this. I find it incredibly annoying. My '02 TB with the same engine did not do this.
 
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